LONDON — A polar bear was shot and killed on Saturday after it attacked and injured a guard from a cruise ship that had stopped at an Arctic archipelago, the Norwegian authorities said.

The death of the bear at the hands of another cruise ship employee drew condemnation on social media, with some calling it “abhorrent” and others questioning killing the polar bear for “acting like a wild animal.”

Moritz Krause, a spokesman for Hapag-Lloyd Cruises, the German operator of the cruise expedition, said on Sunday by phone that “we completely regret what happened” to the bear but that the cruise ship employee had acted in self-defense.

The guard who was attacked, he said, had suffered head injuries but was now responsive and in “stable condition.”

In a statement, Hapag-Lloyd Cruises said the ship, the Bremen, had landed on Spitsbergen, an island in the Svalbard archipelago, between mainland Norway and the North Pole.

The company described the island, part of Norway, as “a large geographical area, about one and a half times the size of Denmark. Landings are possible only in a few places.”

No tourists had disembarked, Mr. Krause said, but four armed guards got off the vessel to inspect and secure the shore. The guards “are armed for safety reasons,” he added. “There are polar bears out there.”

He explained that usually, if a wild bear is seen, guards “shoot into the air” to scare the animal away. On Saturday morning, however, the injured guard did not see the polar bear, he said.

According to the cruise company’s statement: “The incident occurred when the four-person polar bear guard team, who are always on board for these expedition cruises as required by law, prepared for a shore leave. One of the guards was unexpectedly attacked by a polar bear that had not been spotted and he was unable to react himself.”

“There had to be intervention for reasons of self-defense and to protect the life of the attacked person,” the statement added.

The injured guard, who was not identified, was flown by helicopter to a nearby hospital, according to Hapag-Lloyd Cruises.

Mr. Krause said that the company dated to 1891 and that he was not aware of any similar episodes on any previous expedition. The ship, which typically carries a maximum of 150 people, remained at the site for “a couple of hours” to comply with local laws and then moved on, he added

“Hapag-Lloyd Cruises is very aware of its responsibility when traveling in environmentally sensitive areas and respects all nature and wildlife,” the company statement said.

The shooting on the cruise expedition spurred debate on Twitter, with some supporting the guard for defending his colleague.

According to The Associated Press, tourism in the Arctic region is in its peak summer season, and the number of visitors has risen in the past few years. Eighteen cruise ships will be docking at Longyearbyen, Svalbard’s largest settlement, in the next week, according to a port schedule, The A.P. said.

A version of this article appears in print on , on Page A8 of the New York edition with the headline: Polar Bear Is Killed After Attacking Cruise Ship Guard. Order Reprints | Today’s Paper | Subscribe